package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.redisson.client.RedisClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 王同学
 * @since 2024-2-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);

    }
    private BlockingQueue<VoucherOrder>  orderTaks = new ArrayBlockingQueue<>(1024 * 1024);
    private static  final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

//    @PostConstruct
//    private void init () {
//        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
//    }
//    private class VoucherOrderHandler implements Runnable {
//        @Override
//        public void run() {
//            while (true) {
//                // 1. 获取队列中的订单信息
//                try{
//                    VoucherOrder voucherOrder = orderTaks.take();
//                    // 创建订单
//                    handleVoucherOrder(voucherOrder);
//                } catch (Exception e) {
//                    log.error("处理异常", e);
//                }
//            }
//        }
//
//        private void handleVoucherOrder(VoucherOrder voucherOrder) {
//            // 获取用户
//            Long userId = voucherOrder.getUserId();
//            RLock lock = redissonClient.getLock("lock:order:" + userId);
//            boolean isLock = lock.tryLock();
//            // 判断是否获取锁成功
//            if (!isLock) {
//                // 获取锁失败 返回错误信息或重试
//               log.error("不允许重复下单");
//            }
//
//            // 获取代理对象(事务)
//            try {
//                IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//                return proxy.createVoucherOrder(voucherId);
//            } finally {
//                // 手动释放锁
//                lock.unlock();
//            }
//
//        }
//    }



//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        // 获取用户
//        Long userId = UserHolder.getUser().getId();
//        // 1.执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),
//                voucherId.toString(), userId.toString()
//        );
//
//        // 2.判断结果是否为0
//        int r = result.intValue();
//        if (r != 0) {
//            // 2.1 不为0  代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//
//        }
//
//        // 2.2 为0 有购买资格 把下单信息保存到阻塞队列
//        long orderId = redisIdWorker.nextId("order");
//        // TODO 保存阻塞队列
//
//        return Result.ok(orderId);
//    }

    @Override
    public Result seckillVoucher(Long voucherId) {
        // 1.查询优惠券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
        // 2.判断秒杀是否开启
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            // 尚未开始
            return Result.fail("秒杀尚未开始!!");
        }

        // 3.判断秒杀是否已经结束
        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀已经结束!!");
        }
        // 4.判断库存是否充足
        if (voucher.getStock() < 1) {
            return Result.fail("库存不足!!");
        }

        Long userId = UserHolder.getUser().getId();
        // 创建锁对象
        // SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        // 获取锁
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        // 判断是否获取锁成功
        if (!isLock) {
            // 获取锁失败 返回错误信息或重试
            return Result.fail("不允许重复下单");
        }

        // 获取代理对象(事务)
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            // 手动释放锁
            lock.unlock();
        }

    }

    @Transactional
    public Result createVoucherOrder(Long voucherId) {
        // 一人一单的判断
        Long userId = UserHolder.getUser().getId();
            // 6.1 查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
            // 6.2 判断是否存在
            if (count > 0) {
                // 用户已经下过单了
                return Result.fail("用户已经购买过一次了!");
            }

            // 5.扣减库存
            boolean success = seckillVoucherService.update()
                    .setSql("stock = stock - 1") // set stock = stock - 1
                    .eq("voucher_id", voucherId).gt("stock", 0) // where id = ? and stock > 0 ?
                    .update();
            if (!success) {
                // 如果扣减失败
                return Result.fail("库存不足");
            }

            // 6.创建订单
            VoucherOrder voucherOrder = new VoucherOrder();
            // 6.1 订单id
            long orderId = redisIdWorker.nextId("order");
            voucherOrder.setId(orderId);
            // 6.2 用户id
            voucherOrder.setUserId(userId);
            // 6.3 代金券id
            voucherOrder.setVoucherId(voucherId);
            save(voucherOrder); // 将订单写入db
            // 放入阻塞队列
            // orderTaks.add(voucherOrder)
            // 获取代理对象
            // 7. 返回订单id
            return Result.ok(orderId);

    }
}
